Effect of defects in Heusler alloy thin films on spin-dependent tunnelling characteristics of Co2MnSi/MgO/Co2MnSi and Co2MnGe/MgO/Co2MnGe magnetic tunnel junctions
Yamamoto, M; Ishikawa, T; Taira, T; Li, GF; Matsuda, K; Uemura, T
| HERO ID | 4797518 |
|---|---|
| In Press | No |
| Year | 2010 |
| Title | Effect of defects in Heusler alloy thin films on spin-dependent tunnelling characteristics of Co2MnSi/MgO/Co2MnSi and Co2MnGe/MgO/Co2MnGe magnetic tunnel junctions |
| Authors | Yamamoto, M; Ishikawa, T; Taira, T; Li, GF; Matsuda, K; Uemura, T |
| Journal | Journal of Physics: Condensed Matter |
| Volume | 22 |
| Issue | 16 |
| Page Numbers | 164212 |
| Abstract | Fully epitaxial magnetic tunnel junctions (MTJs) with Co-based Heusler alloy Co(2)MnSi electrodes and a MgO tunnel barrier were fabricated with various values of Mn composition α for Co(2)Mn(α)Si in Co(2)Mn(α)Si/MgO/Co(2)Mn(α)Si MTJs. The tunnel magnetoresistance (TMR) ratios at both 4.2 K and room temperature (RT) increased systematically with increasing α in Co(2)Mn(α)Si electrodes from Mn-deficient compositions (α < 1) up to a certain Mn-rich composition (α > 1), demonstrating high TMR ratios of 1135% at 4.2 K and 236% at RT for MTJs with Mn-rich Co(2)Mn(α)Si electrodes with α = 1.29. Identically fabricated Co(2)Mn(β)Ge(δ)/MgO/Co(2)Mn(β)Ge(δ) (δ = 0.38) MTJs showed similar dependence of the TMR ratio on Mn composition β, demonstrating relatively high TMR ratios of 650% at 4.2 K and 220% at RT for β = 1.40. The Mn composition dependence of the TMR ratio at both 4.2 K and RT observed commonly for both Co(2)MnSi/MgO/Co(2)MnSi and Co(2)MnGe/MgO/Co(2)MnGe MTJs can be attributed to suppressed minority-spin in-gap states around the Fermi level for Mn-rich Co(2)MnSi and Co(2)MnGe electrodes. |
| Doi | 10.1088/0953-8984/22/16/164212 |
| Pmid | 21386418 |
| Wosid | WOS:000276353200016 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |